1. Field of the Invention
The present invention relates to novel .alpha.-monoolefin based graft copolymers, to a process for the production thereof and to the use of such novel copolymers, particularly as agents for compatibilizing at least two normally incompatible thermoplastic polymers.
2. Description of the Prior Art
It is known to this art to compatibilize two normally incompatible polymers, in certain specific mixtures, by combining them with a third polymer, which is partially compatible with each of such polymers.
Thus, for example, various third polymers have been proposed for polypropylene/polyamide mixtures:
In the Japanese Patent (Mitsubishi Rayon) published under No. 70-030943, a composition is described comprising polypropylene, polyamide and polypropylene grafted with maleic anhydride.
In the Japanese Patent (Mitsui) published under No. 59-149940, a composition was claimed containing polypropylene, polyamide and an ethylenepropylene copolymer grafted with maleic anhydride.
In the French patent (Mitsubishi Rayon) published under No. FR 2,107,538, a composition is described including polypropylene and glass fiber-reinforced polyamide, and rendered compatible by adding thereto a propylene/.alpha.-olefin/polyamide graft copolymer. This graft copolymer is prepared by polycondensation of an aminoacid in the presence of propylene copolymer previously grafted with maleic anhydride.
In the Japanese Patent (Toa Gosei/Mitsui Toatsu) published under No. 60-233131, a graft copolymer is described for making compatible a mixture of polypropylene and polyvinyl chloride. This graft copolymer is prepared by reacting a polypropylene modified with 2 to 20% by weight of maleic anhydride with a polymethyl methacrylate having a terminal hydroxyl group.